scholarly journals Future supply and demand of net primary production in the Sahel

2016 ◽  
Author(s):  
Florian Sallaba ◽  
Stefan Olin ◽  
Kerstin Engström ◽  
Abdulahakim M. Abdi ◽  
Niklas Boke-Olén ◽  
...  
Keyword(s):  
Population Growth ◽  
Primary Production ◽  
21St Century ◽  
Net Primary Production ◽  
Local Level ◽  
Supply And Demand ◽  
Human Consumption ◽  
Demand Model ◽  
Representative Concentration Pathways ◽  
Increasing Demand

Abstract. In the 21st century, climate change in combination with increasing demand, mainly from population growth, will exert greater pressure on the ecosystems of the Sahel to supply food and feed resources. The balance between supply and demand (annual biomass required for human consumption) serves as a key metric for quantifying basic resource shortfalls over broad regions. Here we apply an exploratory modelling framework to analyze the variations in the timing and geography of different NPP (net primary production) supply-demand scenarios (with distinct assumptions determining supply and demand) for the 21st century Sahel. We achieve this by coupling a simple NPP supply model (forced with projections from four representative concentration pathways) with a global, reduced-complexity demand model (driven by socio-economic data and assumptions derived from five shared socio-economic pathways). For the scenario that deviates least from current socio-economic and climate trends, we find that per capita NPP outstrips its supply in the 2070s, while by 2050, half the countries in the Sahel experience NPP shortfalls. We also find that despite variations in the timing of the onset of NPP shortfalls, demand cannot consistently be met across the majority of scenarios. Moreover, large between-country variations are shown across the scenarios where by the year 2050, some countries consistently experience shortage, others surplus while yet others shift from surplus to shortage. At the local level (i.e. grid cell) hotspots of total NPP shortfall consistently occur in the same locations across all scenarios, but vary in size and magnitude. These hotspots are linked to population density and high demand. For all scenarios, total simulated NPP supply doubles by 2050 but is outpaced by increasing demand due to a combination of population growth and adoption of a diets rich in animal products. Finally, variations in the timing of onset and end of supply shortfalls stem from the assumptions that underpin the shared socio-economic pathways rather than the representative concentration pathways. Our results suggest that the UN sustainable development goals for eradicating hunger are at high risk for failure. This emphasizes the importance of policy interventions such as the implementation of sustainable and healthy diets, family planning, reducing yield gaps, and encouraging transfer of resources to impoverished areas via trade relations.

scholarly journals Future supply and demand of net primary production in the Sahel

2017 ◽  
Vol 8 (4) ◽  
pp. 1191-1221 ◽  
Author(s):  
Florian Sallaba ◽  
Stefan Olin ◽  
Kerstin Engström ◽  
Abdulhakim M. Abdi ◽  
Niklas Boke-Olén ◽  
...  
Keyword(s):  
Population Growth ◽  
Primary Production ◽  
21St Century ◽  
Net Primary Production ◽  
Local Level ◽  
Supply And Demand ◽  
Human Consumption ◽  
Demand Model ◽  
Climate Trends ◽  
Increasing Demand

Abstract. In the 21st century, climate change in combination with increasing demand, mainly from population growth, will exert greater pressure on the ecosystems of the Sahel to supply food and feed resources. The balance between supply and demand, defined as the annual biomass required for human consumption, serves as a key metric for quantifying basic resource shortfalls over broad regions.Here we apply an exploratory modelling framework to analyse the variations in the timing and geography of different NPP (net primary production) supply–demand scenarios, with distinct assumptions determining supply and demand, for the 21st century Sahel. We achieve this by coupling a simple NPP supply model forced with projections from four representative concentration pathways with a global, reduced-complexity demand model driven by socio-economic data and assumptions derived from five shared socio-economic pathways.For the scenario that deviates least from current socio-economic and climate trends, we find that per capita NPP begins to outstrip supply in the 2040s, while by 2050 half the countries in the Sahel experience NPP shortfalls. We also find that despite variations in the timing of the onset of NPP shortfalls, demand cannot consistently be met across the majority of scenarios. Moreover, large between-country variations are shown across the scenarios, in which by the year 2050 some countries consistently experience shortage or surplus, while others shift from surplus to shortage. At the local level (i.e. grid cell), hotspots of total NPP shortfall consistently occur in the same locations across all scenarios but vary in size and magnitude. These hotspots are linked to population density and high demand. For all scenarios, total simulated NPP supply doubles by 2050 but is outpaced by increasing demand due to a combination of population growth and the adoption of diets rich in animal products. Finally, variations in the timing of the onset and end of supply shortfalls stem from the assumptions that underpin the shared socio-economic pathways rather than the representative concentration pathways.Our results suggest that the UN sustainable development goals for eradicating hunger are at high risk for failure. This emphasizes the importance of policy interventions such as the implementation of sustainable and healthy diets, family planning, reducing yield gaps, and encouraging the transfer of resources to impoverished areas via trade relations.

scholarly journals Drivers and uncertainties of future global marine primary production in marine ecosystem models

2015 ◽  
Vol 12 (23) ◽  
pp. 6955-6984 ◽  
Author(s):  
C. Laufkötter ◽  
M. Vogt ◽  
N. Gruber ◽  
M. Aita-Noguchi ◽  
O. Aumont ◽  
...  
Keyword(s):  
Primary Production ◽  
Nutrient Limitation ◽  
21St Century ◽  
Net Primary Production ◽  
Marine Ecosystem ◽  
Phytoplankton Growth ◽  
Strong Increase ◽  
Ecosystem Models ◽  
Low Latitudes ◽  
Marine Ecosystem Models

Abstract. Past model studies have projected a global decrease in marine net primary production (NPP) over the 21st century, but these studies focused on the multi-model mean rather than on the large inter-model differences. Here, we analyze model-simulated changes in NPP for the 21st century under IPCC's high-emission scenario RCP8.5. We use a suite of nine coupled carbon–climate Earth system models with embedded marine ecosystem models and focus on the spread between the different models and the underlying reasons. Globally, NPP decreases in five out of the nine models over the course of the 21st century, while three show no significant trend and one even simulates an increase. The largest model spread occurs in the low latitudes (between 30° S and 30° N), with individual models simulating relative changes between −25 and +40 %. Of the seven models diagnosing a net decrease in NPP in the low latitudes, only three simulate this to be a consequence of the classical interpretation, i.e., a stronger nutrient limitation due to increased stratification leading to reduced phytoplankton growth. In the other four, warming-induced increases in phytoplankton growth outbalance the stronger nutrient limitation. However, temperature-driven increases in grazing and other loss processes cause a net decrease in phytoplankton biomass and reduce NPP despite higher growth rates. One model projects a strong increase in NPP in the low latitudes, caused by an intensification of the microbial loop, while NPP in the remaining model changes by less than 0.5 %. While models consistently project increases NPP in the Southern Ocean, the regional inter-model range is also very substantial. In most models, this increase in NPP is driven by temperature, but it is also modulated by changes in light, macronutrients and iron as well as grazing. Overall, current projections of future changes in global marine NPP are subject to large uncertainties and necessitate a dedicated and sustained effort to improve the models and the concepts and data that guide their development.

scholarly journals Impacts of climate variability and extremes on global net primary production in the first decade of the 21st century

2015 ◽  
Vol 25 (9) ◽  
pp. 1027-1044 ◽  
Author(s):  
Shufen Pan ◽  
Hanqin Tian ◽  
Shree R. S. Dangal ◽  
Zhiyun Ouyang ◽  
Chaoqun Lu ◽  
...  
Keyword(s):  
Climate Variability ◽  
Primary Production ◽  
21St Century ◽  
Net Primary Production

scholarly journals Global patterns in human consumption of net primary production

Nature ◽  
2004 ◽  
Vol 429 (6994) ◽  
pp. 870-873 ◽  
Author(s):  
Marc L. Imhoff ◽  
Lahouari Bounoua ◽  
Taylor Ricketts ◽  
Colby Loucks ◽  
Robert Harriss ◽  
...  
Keyword(s):  
Primary Production ◽  
Net Primary Production ◽  
Human Consumption ◽  
Global Patterns

Causes of uncertainty in China's net primary production over the 21st century projected by the CMIP5 Earth system models

2015 ◽  
Vol 36 (5) ◽  
pp. 2323-2334 ◽  
Author(s):  
Tao Wang ◽  
Xin Lin ◽  
Yongwen Liu ◽  
Sarah Dantec-Nédélec ◽  
Catherine Ottlé
Keyword(s):  
Primary Production ◽  
21St Century ◽  
Net Primary Production ◽  
Earth System ◽  
System Models ◽  
Earth System Models

scholarly journals Drivers and uncertainties of future global marine primary production in marine ecosystem models

2015 ◽  
Vol 12 (4) ◽  
pp. 3731-3824 ◽  
Author(s):  
C. Laufkötter ◽  
M. Vogt ◽  
N. Gruber ◽  
M. Aita-Noguchi ◽  
O. Aumont ◽  
...  
Keyword(s):  
Primary Production ◽  
Nutrient Limitation ◽  
21St Century ◽  
Net Primary Production ◽  
Marine Ecosystem ◽  
Strong Increase ◽  
Ecosystem Models ◽  
Model Studies ◽  
Low Latitudes ◽  
Marine Ecosystem Models

Abstract. Past model studies have projected a global decrease in marine net primary production (NPP) over the 21st century, but these studies focused on the multi-model mean and mostly ignored the large inter-model differences. Here, we analyze model simulated changes of NPP for the 21st century under IPCC's high emission scenario RCP8.5 using a suite of nine coupled carbon–climate Earth System Models with embedded marine ecosystem models with a focus on the spread between the different models and the underlying reasons. Globally, five out of the nine models show a decrease in NPP over the course of the 21st century, while three show no significant trend and one even simulates an increase. The largest model spread occurs in the low latitudes (between 30° S and 30° N), with individual models simulating relative changes between −25 and +40%. In this region, the inter-quartile range of the differences between the 2012–2031 average and the 2081–2100 average is up to 3 mol C m-2 yr-1. These large differences in future change mirror large differences in present day NPP. Of the seven models diagnosing a net decrease in NPP in the low latitudes, only three simulate this to be a consequence of the classical interpretation, i.e., a stronger nutrient limitation due to increased stratification and reduced upwelling. In the other four, warming-induced increases in phytoplankton growth outbalance the stronger nutrient limitation. However, temperature-driven increases in grazing and other loss processes cause a net decrease in phytoplankton biomass and reduces NPP despite higher growth rates. One model projects a strong increase in NPP in the low latitudes, caused by an intensification of the microbial loop, while the remaining model simulates changes of less than 0.5%. While there is more consistency in the modeled increase in NPP in the Southern Ocean, the regional inter-model range is also very substantial. In most models, this increase in NPP is driven by temperature, but is also modulated by changes in light, macronutrients and iron as well as grazing. Overall, current projections of future changes in global marine NPP are subject to large uncertainties and necessitate a dedicated and sustained effort to improve the models and the concepts and data that guide their development.

scholarly journals Consumer savings, price, and emissions impacts of increasing demand response in the Midcontinent electricity market

2018 ◽  
Author(s):  
Steve Dahlke ◽  
Matt Prorok
Keyword(s):  
Co2 Emissions ◽  
Demand Response ◽  
Electricity Market ◽  
Supply And Demand ◽  
Operating Conditions ◽  
High Price ◽  
Demand Model ◽  
Emissions Reductions ◽  
Market Effects ◽  
Increasing Demand

This paper estimates consumer savings, CO2 emissions reductions, and price effects from increasing demand response (DR) dispatch in the Midcontinent Independent System Operator (MISO) electricity market. To quantify market effects, we develop a dynamic supply and demand model to explore a range of DR deployment scenarios. The study is motivated by the existence of regulatory and market rule barriers to market-based deployment of DR resources in the MISO region. We show annual consumer savings from increased market-based DR can vary from $1.3 million to $17.6 million under typical peak operating conditions, depending on the amount of DR resources available for market dispatch and the frequency of deployment. Consumer savings and other market effects increase exponentially during atypical periods with tight supply and high prices. Additionally, we find that DR deployment often reduces CO2 emissions, but the magnitude of emissions reductions varies depending on the emissions content of marginal generation at the time and location of deployment. The results of this study suggest regulators and other stakeholders should focus policy efforts to reducing regulatory barriers to DR deployment in wholesale markets, particularly in locations that experience high price spikes, to improve market efficiency and achieve cost savings for consumers.

scholarly journals Acidification, deoxygenation, nutrient and biomasses decline in a warming Mediterranean Sea

2021 ◽  
Author(s):  
Marco Reale ◽  
Gianpiero Cossarini ◽  
Paolo Lazzari ◽  
Tomas Lovato ◽  
Giorgio Bolzon ◽  
...  
Keyword(s):  
Primary Production ◽  
Mediterranean Sea ◽  
Water Column ◽  
21St Century ◽  
Dissolved Inorganic Carbon ◽  
Net Primary Production ◽  
Eastern Mediterranean ◽  
Marine Ecosystems ◽  
Global Ocean ◽  
Co2 Absorption

Abstract. The projected warming, nutrient decline, changes in net primary production, deoxygenation and acidification of the global ocean will dramatically affect marine ecosystems during the 21st century. Here we assess the climate change-related impacts in the marine ecosystems of the Mediterranean Sea in the middle and at the end of the 21st century using high-resolution projections of the physical and biogeochemical state of the basin under the Representative Concentration Pathways (RCPs) 4.5 and 8.5. The analysis shows significant changes in the dissolved nutrient content of the euphotic and intermediate layers of the basin, net primary production, phytoplankton respiration and carbon stock (including phytoplankton, zooplankton, bacterial biomass and particulate organic matter). The projections also show a uniform surface and subsurface reduction in the oxygen concentration driven by the warming of the water column and by the increase in respiration. Moreover, we observe an acidification in the upper water column, linked to the increase in the dissolved inorganic carbon content of the water column due to CO2 absorption from the atmosphere and the increase in respiration. The projected changes are stronger in the eastern Mediterranean due to the limited influence, in that part of the basin, of the exchanges in the Strait of Gibraltar.

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